This invention relates to the transfer of data, such as the transfer of data between a modem controller chip and a personal computer.
Generally, modem chips use serial shift first-in first-out buffers, or serial shift FIFOs. Serial shift FIFOs have data written in or read out serially using a serial register. The 16550 chip produced by National from Santa Clara, Calif. is an universal asynchronous receiver transmitter or UART which uses serial shift FIFOs to buffer a serial-to-parallel interface. In the transmitter UART FIFO, data is written to the UART FIFO in parallel from a personal computer or PC and sent out of the UART FIFO serially. In the receiver UART FIFO, data is written in to the UART FIFO serially and read out to the PC in parallel.